Washing machine and laundry amount detection apparatus thereof

ABSTRACT

Disclosed herein are a washing machine that amplifies the displacement of a tub according to input of laundry such that the displacement of the tub is accurately sensed by a sensor module and a laundry amount detection apparatus thereof. The washing machine includes a housing forming an external appearance thereof, a tub provided in the housing to contain water, an amplification unit to amplify displacement of the tub, and a sensor module to sense weight of laundry using the amplified displacement of the tub.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Korean PatentApplication No. 2010-0019765, filed on Mar. 5, 2010 in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference.

BACKGROUND

1. Field

Embodiments of the present invention relate to a washing machine thatamplifies the displacement of a tub according to input of laundry suchthat the displacement of the tub is sensed by a sensor module and alaundry amount detection apparatus thereof.

2. Description of the Related Art

Generally, a washing machine (normally, a drum washing machine) includesa tub mounted in a housing to receive water containing a detergent,i.e., detergent water, a drum rotatably mounted in the tub to washlaundry, and a door hingedly coupled to the front of the housing to openand close an opening formed at the front of the housing. Laundry is putinto the drum through the opening of the housing, a predetermined amountof detergent water is supplied into the tub, and the drum is rotated towash the laundry.

When a user selects a washing course, the weight of the laundry issensed to decide the amount of wash water, wash water sufficient to wetthe laundry is supplied into the tub together with a detergent accordingto the decided amount of wash water, and the drum is rotated to performa washing cycle and a spin-drying cycle.

When the weight of the laundry is accurately sensed, the amount of watercorresponding to the sensed weight of the laundry is supplied to washthe laundry. Consequently, the amount of water and power used isreduced, thereby reducing energy consumption.

In the related art, laundry in the drum is used as an inertia load, andinertia is estimated to sense the weight of the laundry. For example,predetermined voltage is applied to a motor to accelerate the drum, andinertia is estimated using change in voltage and velocity of the motorduring acceleration of the drum to sense the weight of the laundry.

In this method of sensing the weight of the laundry, no additionalsensor is provided, thereby reducing material costs. However, a weightsensing error may occur according to the waveform of the voltage. Also,washing machines may have different deviations, with the result that anerror may occur during sensing of the weight of the laundry.

Also, the displacement of the tub according to the descent of the tubdue to input of laundry may be measured to estimate the amount oflaundry. If the descent of the tub according to the input of the laundryis slight, however, a weight sensing error may occur. In particular,when a small amount of laundry is input, the descent of the tub is veryslight, with the result that weight detection may fail.

SUMMARY

It is an aspect of to provide a washing machine that amplifies thedisplacement of a tub according to input of laundry such that thedisplacement of the tub is accurately sensed by a sensor module and alaundry amount detection apparatus thereof.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be obvious from the description, or may belearned by practice of the invention.

In accordance with one aspect, a washing machine includes a housingforming an external appearance thereof, a tub provided in the housing tocontain water, an amplification unit to amplify displacement of the tub,and a sensor module to sense weight of laundry using the amplifieddisplacement of the tub.

The amplification unit may include a lever configured to be rotatedabout a predetermined shaft in proportion to the displacement of the tubto amplify the displacement of the tub and a fixing member rotatablycoupled to a predetermined region of the lever at one end thereof toform the shaft of the lever.

The lever may include an input end provided at the tub such that thedisplacement of the tub is transmitted to the input end and an outputend provided opposite to the input end to amplify and transmit thedisplacement of the tub to the sensor module.

The lever may be formed such that a length from the input end of thelever to the shaft of the lever is shorter than a length from the outputend of the lever to the shaft of the lever.

The washing machine may further include a damper provided below the tubto dampen vibration, and the damper may include a cylinder mounted at abottom of the housing and a piston provided below the tub such that thepiston is advanced and retreated in the cylinder.

The piston may be coupled to the input end of the lever provided belowthe tub such that the displacement of the tub is transmitted to theinput end of the lever.

The fixing member may have the other end fixedly mounted to an outercircumference of the cylinder.

The sensor module may include an optical sensor module mounted at a sideof the housing, and the output end of the lever may include a reflectionplate corresponding to the optical sensor module.

The sensor module may include a capacitance sensor module mounted at aside of the housing and the output end of the lever.

The capacitance sensor module may include a first electrode platemounted at the side of the housing and a second electrode plate mountedat the output end of the lever such that the second electrode platefaces the first electrode plate.

The capacitance sensor module may constitute an RC circuit and/or an LCcircuit using change in capacitance between the first electrode plateand the second electrode plate.

The sensor module may include a resistor sensor module mounted at a sideof the housing and the output end of the lever.

The resistor sensor module may include a variable resistor mounted atthe side of the housing and a resistance adjuster mounted at the outputend of the lever such that the resistance adjuster is connected to thevariable resistor to adjust a resistance value of the variable resistor.

The resistor sensor module may constitute an RC circuit or an RR circuitusing change in output voltage of the variable resistor.

In accordance with another aspect of the present invention, a washingmachine includes a housing, a tub provided in the housing to containwater, a lever having an output end to amplify displacement of the tubtransmitted to an input end according to input of laundry into thewashing machine, and a sensor module configured to measure displacementof the output end of the lever to sense weight of the laundry.

The washing machine may further include a fixing member coupled to apredetermined region of the lever to form a shaft of the lever, and thelever may be rotated about the shaft such that the displacement of thetub transmitted to the input end of the lever is amplified at the outputend of the lever.

In accordance with a further aspect of the present invention, a laundryamount detection apparatus of a washing machine includes a sensor moduleconfigured to measure descent of a tub to sense weight of laundry and alever configured to be rotated about a shaft to amplify the descent ofthe tub such that the descent of the tub is sensed by the sensor module,wherein the lever includes an input end fixedly mounted to the tub suchthat the descent of the tub is transmitted to the input end and anoutput end provided opposite to the sensor module.

The laundry amount detection apparatus may further include a fixingmember rotatably coupled to a predetermined region of the lever at oneend thereof to form the shaft of the lever.

The sensor module may include an optical sensor module, and the outputend of the lever may include a reflection plate corresponding to theoptical sensor module.

The sensor module may include a capacitance sensor module, and thecapacitance sensor module may include a first electrode plate having apredetermined size and a second electrode plate mounted at the outputend of the lever such that the second electrode plate corresponds to thefirst electrode plate.

The sensor module may include a resistor sensor module, and the resistorsensor module may include a variable resistor and a resistance adjustermounted at the output end of the lever such that the resistance adjusteris connected to the variable resistor to adjust a resistance value ofthe variable resistor.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the invention will become apparent andmore readily appreciated from the following description of theembodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a schematic side sectional view illustrating the structure ofa drum washing machine according to an embodiment of the presentinvention;

FIG. 2 is a front sectional view of the drum washing machine shown inFIG. 1;

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a view illustrating the operation of a lever shown in FIG. 3;

FIG. 5 is a schematic control block diagram of a sensor module shown inFIG. 3;

FIG. 6 is a control flow chart illustrating a process of sensing imagechange based on displacement of an object, which is changed dependingupon the weight of laundry, in the drum washing machine shown in FIG. 2to confirm the weight of the laundry;

FIG. 7 is a view illustrating a pixel mapping process to determine acorrelation coefficient between a reference image and a current image ofFIG. 6;

FIG. 8 is a partial view illustrating a drum washing machine accordingto another embodiment of the present invention;

FIG. 9 is a view illustrating the operation of a lever shown in FIG. 8;

FIG. 10 is a partial view illustrating a drum washing machine accordingto a further embodiment of the present invention; and

FIG. 11 is a view illustrating the operation of a lever shown in FIG.10.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout.

FIG. 1 is a schematic side sectional view illustrating the structure ofa drum washing machine 1-1 according to an embodiment of the presentinvention. FIG. 2 is a front sectional view of the drum washing machineshown in FIG. 1. FIG. 3 is a partially enlarged view of FIG. 2. FIG. 4is a view illustrating the operation of a lever shown in FIG. 3.

As shown in FIGS. 1 to 4, the drum washing machine 1-1 includes abox-shaped housing 10 forming the external appearance thereof, a tub 20provided in the housing 10 to contain water, a cylindrical drum 30rotatably mounted in the tub 20, the drum 30 having through holes 31through which water and air pass, and a drive motor 40 to transmitrotational force to the drum 30 such that the drum 30 is rotated to washand spin-dry laundry in the drum 30.

The tub 20 and the drum 30 are partially open at the front middleportions thereof to constitute inlet ports 20 a and 30 a through whichlaundry is put into or removed from the drum 30. To the front of thehousing 10 is hingedly coupled a door 50 to open and close the inletports 20 a and 30 a of the tub 20 and the drum 30.

At the inner circumference of the drum 30 are arranged lifters 32 atpredetermined intervals. During rotation of the drum 30 in alternatingdirections, the laundry is lifted and dropped by the lifters 32, bywhich the laundry is washed.

In this embodiment, the drum washing machine 1-1 also includessuspension springs 60 disposed above the tub 20 to elastically supportthe tub 20 and dampers 70 disposed below the tub 20 to dampen vibration,thereby preventing the occurrence of vibration during the operation ofthe drum washing machine 1-1.

The suspension springs 60 and the dampers 70 movably support the tub 20above and below the tub 20. That is, vibration generated from the drum30 during rotation of the drum 30 is transmitted to the tub 20, with theresult that the tub 20 is vibrated in all directions, for example backand forth, side to side, and up and down. Such vibration of the tub 20is dampened by the suspension springs 60 and the dampers 70.

Each of the dampers 70 may be mounted to the tub 20 at one end 70 athereof and to a bottom 10 a of the housing 10 at the other end 70 bthereof via an intervention member 10 c to dampen vibration generatedfrom the tub 20 during rotation of the drum 30.

Each of the dampers 70 includes a cylinder 71 having one open end 71 aand the other end 71 b mounted to the bottom 10 a of the housing 10 ofthe washing machine, a piston 72 having one end 72 a mounted in thecylinder 71 in an advancing and retreating manner and the other end 72 bmounted to the bottom of the tub 20, and a friction pad 73 having onemajor surface mounted to the piston 72 and the other major surface intight contact with the inner surface of the cylinder 71 such that thefriction pad 73 is advanced and retreated in the cylinder 71 togetherwith the piston 72 to dampen vibration through friction between thefriction pad 73 and the cylinder 71.

When vibration from the tub 20 is transmitted to each of the dampers 70,therefore, the friction pad 73 moves along the inner surface of thecylinder 71 according to the movement of the piston 72 to dampenvibration transmitted from the tub 20 through friction between thefriction pad 73 and the cylinder 71.

Meanwhile, a fixing member 80 is mounted to the outer circumference ofthe cylinder 71 such that the fixing member 80 is coupled to apredetermined region of a lever 100, which will be described later. Oneend 81 of the fixing member 80 is fixedly mounted to the cylinder 71 viascrews 83, and the other end 82 of the fixing member 80 is fixedlymounted to the predetermined region of the lever 100, with the resultthat the lever 100 is rotated about the predetermined region as the tub20 descends.

In the drawings, the fixing member 80 is mounted to the outercircumference of the cylinder 71 although the fixing member 80 may beformed in various shapes and mounted at the bottom 10 a or a side 10 bof the housing 10.

In this embodiment, the drum washing machine 1-1 also includes a sensormodule 90 to sense displacement of the tub 20 before and after laundryis put into the drum 30 to confirm laundry amount, i.e., the weight ofthe laundry. The sensor module 90 may be mounted to the side 10 b of thehousing 10 such that the sensor module 90 is opposite to the outercircumference of the tub 20.

When laundry is put into the drum 30, the tub 20 descends vertically.The heavier the laundry is, the more the tub 20 descends.

The sensor module 90 senses displacement of the tub 20 before and afterthe laundry is put into the drum 30 to confirm the weight of thelaundry.

The sensor module 90 may be an optical sensor module, which will bedescribed in detail with reference to FIGS. 4 to 6.

In this embodiment, the drum washing machine 1-1 also includes a lever100 to amplify the displacement of the tub 20 such that displacement ofthe tub 20 is sensed by the optical sensor module 90.

The lever 100 is long and disposed between the lower part of the tub 20and the optical sensor module 90. The lever 100 includes an input end110 fixedly mounted to the tub 20 and an output end 120 opposite to theinput end 110 such that the output end 120 faces the optical sensormodule 90.

As shown in FIGS. 3 and 4, the input end 110 of the lever 100 may becoupled to a position where the piston 72 of a corresponding one of thedampers 70 is mounted at the lower part of the tub 20. The input end 110of the lever 100 may be coupled to any region of the tub 20 as long asthe input end 110 of the lever 100 amplifies or magnifies microdisplacement of the tub 20 such that the displacement of the tub 20 issensed by the optical sensor module 90.

The lever 100 is provided with a rotation shaft 130 coupled to thefixing member 80 such that the rotation shaft 130 is adjacent to theinput end 110 of the lever 100. The rotation shaft 130 serves as arotation center of the lever 100.

The output end 120 of the lever 100 amplifies micro displacement of thetub 20 input to the input end 110 of the lever 100. That is, on theassumption that the distance from the input end 110 of the lever 100 tothe rotation shaft 130 is a and the distance from the rotation shaft 130to the output end 120 of the lever 100 is b, the output end 120 of thelever 100 amplifies micro displacement of the tub 20 by b/a according tothe principle of the lever.

The output end 120 of the lever 100 may includes a reflection plate 121to reflect light emitted from the optical module sensor 90. Thereflection plate 121 may not be provided as long as the width of theoutput end 120 of the lever 100 facing the optical sensor module issufficiently large, and the output end 120 of the lever 100 is formed ofa reflective material to reflect light.

When laundry is put into the drum 30, the tub 20 descends. As a result,the lever 100 is rotated about the rotation shaft 130 as shown in FIG.4. At this time, the lever 100 amplifies micro displacement of the tub20 by b/a such that the displacement of the tub 20 is sensed by theoptical module sensor 90.

For example, if b/a is 4, the displacement of the output end 120 of thelever 100 is four times that of the tub 20. That is, on the assumptionthat the displacement of the tub 20 is 1 mm, the displacement of theoutput end 120 of the lever 100 is amplified to 4 mm, which issufficient for the optical sensor module 90 to sense the weight oflaundry.

In this way, the displacement of the tub 20 is amplified according tothe principle of the lever using the optical sensor module 90 and thelever 100, and the amplified displacement of the tub 20 is sufficientfor the optical sensor module 90 to sense the weight of laundry.Although the tub 20 descends very slightly, therefore, the weight oflaundry is sensed by the optical sensor module 90.

Also, the use of the optical sensor module 90 and the lever 100 mayreduce the occurrence of weight sensing errors based on a voltagewaveform as compared with the use of a motor in the related art.

FIG. 5 is a schematic control block diagram of the optical sensor moduleshown in FIG. 3. FIG. 6 is a control flow chart illustrating a processof sensing image change based on displacement of an object, which ischanged depending upon the weight of laundry, in the drum washingmachine shown in FIG. 2 to confirm the weight of the laundry. FIG. 7 isa view illustrating a pixel mapping process to determine a correlationcoefficient between a reference image and a current image of FIG. 6.

As shown in FIGS. 5 to 7, the optical sensor module 90 may include alight source 91, a lens 92, an image sensor 93 and an image processor94.

The light source 91 may be a light emitting diode (LED) or a laser.However, it is not limited thereof. The light source 91 irradiates lightto the output end 120 of the lever 100.

The lens 92 adjusts the direction of the light emitted from the lightsource 91 such that the light is directed to the output end 120 of thelever 100 and the direction of the light reflected from the output end120 of the lever 100 such that the light is directed to the image sensor93.

The image sensor 93 receives the light reflected from the output end 120of the lever 100 to create an image of the output end 120 of the lever100. The light source 91 and the image sensor 93 may be incorporatedinto the sensor module 90 to achieve structural integration.

The image processor 94 calculates displacement of two images using acommon correlation algorithm to compare the two images.

A controller 200 communicates with the image processor 94 to receive theimage change between the two images from the image processor 94 andretrieves the weight of laundry corresponding to the image change from amemory 210 thereof to confirm the weight of the laundry.

Hereinafter, a process of sensing image change based on displacement ofthe tub to confirm the weight of laundry will be described withreference to FIG. 6.

First, the controller 200 commands the optical sensor module 90 to senseand store an image of the output end 120 of the lever 100 before laundryis put into the drum 30. However, it is also understood that the imageof output end 120 of the lever 100 can be pre-stored.

Upon receiving the command from the controller 200, the optical sensormodule 90 irradiates light to the output end 120 of the lever 100through the light source 91 (S100). The light emitted from the lightsource 91 is irradiated to the output end 120 of the lever 100 throughthe lens 92. The light irradiated to the output end 120 of the lever 100is reflected from the output end 120 of the lever 100 and is received bythe image sensor 93 through the lens 92.

The optical sensor module 90 senses an image of the output end 120 ofthe lever 100 using the light reflected from the output end 120 of thelever 100 and received by the image sensor 93 (S101).

The controller 200 receives the image of the output end 120 of the lever100 from the optical sensor module 90 to store the same in the memory210 as a reference image of the output end 120 of the lever 100 (S102).At this time, the image of the output end 120 of the lever 100 may bestored in a memory of the optical sensor module 90.

The controller 200 determines whether laundry has been put into the drum30 (S103). The determination as to whether the laundry has been put intothe drum 30 may be achieved based on the operation of the door, alaundry sensor, or a user command.

Upon determining at Operation S103 that the laundry has not been putinto the drum 30, the controller 200 returns to a predetermined routine.

On the other hand, upon determining at Operation S103 that the laundryhas been put into the drum 30, the controller 200 commands the opticalsensor module 90 to sense and store an image of the output end 120 ofthe lever 100 again. At this time, when the laundry has been put intothe drum 30, the output end 120 of the lever 100 is moved in thedirection indicated by an arrow in FIG. 4 according to the weight of thelaundry, with the result that the image of the lever 100 sensed by theoptical sensor module 90 is changed.

According to the command from the controller 200, the optical sensormodule 90 irradiates light to the output end 120 of the lever 100through the light source 91 (S104). At this time, the light emitted fromthe light source 91 is irradiated to the output end 120 of the lever 100through the lens 92, and the light irradiated to the output end 120 ofthe lever 100 is reflected from the output end 120 of the lever 100 andreceived by the image sensor 93 through the lens 92.

The optical sensor module 90 senses an image of the output end 120 ofthe lever 100 using the light source 91 reflected from the output end120 of the lever 100 and received by the image sensor 93 (S105).

The controller 200 receives the image of the output end 120 of the lever100 from the optical sensor module 90 to store the same in the memory210 as a current image of the output end 120 of the lever 100 (S106).

The image processor 94 compares the current image of the output end 120of the lever 100 with the reference image of the output end 120 of thelever 100 to sense the image change of the output end 120 of the lever100 (S107).

Subsequently, the controller 200 retrieves (or detects) the weight oflaundry corresponding to the image change between the reference imageand the current image of the output end 120 of the lever 100 from thememory 210 to confirm the weight of the laundry (S108).

As shown in FIG. 7, the image change based on displacement of the outputend 120 of the lever 100, which is changed depending upon the weight ofthe laundry, is confirmed by comparison between the reference image andthe current image of the output end 120 of the lever 100.

An image of the output end 120 of the lever 100 before the laundry isput into the drum 30 is set as the reference image on which a maskwindow is defined. The mask window is a common portion between thereference image and the current image. When comparing the mask windowwith the current image, the pixels in the mask window are compared withthe total pixels of the input frame although each pixel in the maskwindow may be compared with the most adjacent pixel thereof.

In this embodiment, the mask window (for example, a window of 4×4pixels) is set from the reference image (for example, an image of 12×12pixels), and the mask window is moved with respect to the entirety ofthe current image (for example, an image of 12×12 pixels) by anarbitrary pixel unit (for example, one pixel) to determine a correlationcoefficient.

Comparison between the mask window of the reference image and a firstregion of the current image is performed to determine a correlationcoefficient, and comparison between the mask window of the referenceimage and a second region of the current image is performed to determinea correlation coefficient. This process is repeatedly performed untilcomparison between the mask window of the reference image and an Nregion of the current image is performed.

At the position having the largest correlation efficient, X-axis andY-axis displacement values (image change values) are created. X-axis andY-axis displacement values may include a range from the coordinatevalues (0, 0) of the output end 120 of the lever 100 before the laundryis put into the drum 30 to the maximum coordinate values (n, n) of theoutput end 120 of the lever 100. The maximum displacement value n isdecided based on the entire window size of the current image and themask window size of the reference image.

The obtained image change value, indicating the displacement of theoutput end 120 of the lever 100, is provided to the controller 200 whichuses the image change value to confirm the weight of the laundry.

Hereinafter, another embodiment will be described with reference toFIGS. 8 and 9. Components of this embodiment identical to those of theprevious embodiment are denoted by the same reference numerals, and adescription thereof will not be given. FIG. 8 is a partial viewillustrating a drum washing machine 1-2 according to another embodiment.FIG. 9 is a view illustrating the operation of a lever shown in FIG. 8.

As shown in FIGS. 8 and 9, the drum washing machine 1-2 includes ahousing 10 having a bottom 10 a and a side 10 b to form the externalappearance thereof, a tub 20 provided in the housing 10 to containwater, a capacitance sensor module 300 to measure displacement of thetub 20 according to the weight of laundry, and a lever 100 to amplifythe displacement of the tub 20 such that the displacement of the tub 20is sensed by the capacitance sensor module 300.

The capacitance sensor module 300 includes a first electrode plate 310mounted at the side 10 b of the housing 10 and a second electrode plate320 mounted at an output end 120 of the lever 100 such that the secondelectrode plate 320 corresponds to the first electrode plate 310. Thecapacitance sensor module 300 measures change in capacitance between thefirst and second electrode plates 310 and 320 to confirm displacement ofthe output end 120 of the lever 100 according to the descent of the tuband thus the weight of laundry in the drum washing machine.

The capacitance between the electrode plates 310 and 320 is inverselyproportional to the distance between the electrode plates 310 and 320and is directly proportional to the overlap area between the electrodeplates 310 and 320 as represented by Equation 1. In Equation 1, ∈rindicates permittivity in vacuum and ∈0 indicates dielectric constant. Sindicates the overlap area between the first and second electrode plates310 and 320, and d indicates the distance between the first and secondelectrode plates 310 and 320.

$\begin{matrix}{C = {\varepsilon_{r}\varepsilon_{0}\frac{S}{d}}} & ( {{Equation}\mspace{14mu} 1} )\end{matrix}$

Therefore, the descent of the tub 20 is changed according to the amountof laundry in the drum washing machine, and the displacement of the tub20 is amplified by b/a at the output end 120 of the lever 100. Theoverlap area, i.e., the effective area S, between the first and secondelectrode plates 310 and 320 is changed according to the displacement ofthe tub 20 and the output end 120 of the lever 100, with the result thatthe capacitance between the first and second electrode plates 310 and320 is changed. Therefore, the weight of the laundry in the drum washingmachine is conformed through measurement of the capacitance change.

The capacitance change may be measure using, for example, an RC circuitas shown in FIG. 9. In this case, the capacitance change may becalculated through the measurement of the change in voltage between theelectrode plates 310 and 320.

That is, the first electrode plate 310, the second electrode plate 320,an input voltage (Vin) 330, and a reference resistance (R0) 340constitute the circuit. In this case, a first output voltage outputbetween the electrodes 310 and 320 is measured before laundry is inputinto the drum washing machine, a second output voltage output betweenthe electrodes 310 and 320 is measured after the laundry is input intothe drum washing machine, and the first output voltage and the secondoutput voltage are compared to measure the capacitance change.

Although the capacitance change is not shown in the drawings, the changein resonance frequency between the electrode plates 310 and 320 may bemeasured using a known LC circuit to calculate the capacitance change.

Hereinafter, a further embodiment will be described with reference toFIGS. 10 and 11. Components of this embodiment identical to those of theprevious embodiments are denoted by the same reference numerals, and adescription thereof will not be given. FIG. 10 is a partial viewillustrating a drum washing machine 1-3 according to a furtherembodiment. FIG. 11 is a view illustrating the operation of a levershown in FIG. 10.

As shown in FIGS. 10 and 11, the drum washing machine 1-3 includes ahousing 10 having a bottom 10 a and a side 10 b to form the externalappearance thereof, a tub 20 provided in the housing 10 to containwater, a resistor sensor module 400 to measure displacement of the tub20 according to the weight of laundry, and a lever 100 to amplify thedisplacement of the tub 20 such that the displacement of the tub 20 issensed by the resistor sensor module 400.

The resistor sensor module 400 includes a variable resistor 410 mountedat the side 10 b of the housing 10 and a resistance adjuster 420 mountedat an output end 120 of the lever 100. The resistor sensor module 400measures voltage output from the variable resistor 410 to confirmdisplacement of the output end 120 of the lever 100 according to thedescent of the tub 20.

Therefore, the descent of the tub 20 is changed according to the amountof laundry in the drum washing machine, and the displacement of the tub20 transmitted to an input end 110 of the lever 100 is amplified by b/aat the output end 120 of the lever 100.

The variable resistor 410, the resistance adjuster 420, an input voltage(Vin) 430, and a reference resistance (R0) 440 constitute a circuit. Inthis case, the changes in output voltage according to the displacementof the tub 20 and the output end 120 of the lever 100 are compared tomeasure the weight of laundry.

In the embodiments as described above, the displacement of the tub basedon the weight of the laundry is amplified by the lever such that thedisplacement of the tub is sensed by the sensor module.

As is apparent from the above description, the displacement of the tubdue to the descent of the tub according to the weight of laundry isamplified such that the displacement of the tub is sensed by the sensormodule, thereby achieving automatic and accurate measurement of theweight of the laundry.

Although a few embodiments have been shown and described, it would beappreciated by those skilled in the art that changes may be made inthese embodiments without departing from the principles and spirit ofthe embodiments, the scope of which is defined in the claims and theirequivalents.

1. A washing machine comprising: a housing forming an externalappearance thereof; a tub provided in the housing to contain water; anamplification unit to amplify displacement of the tub; and a sensormodule to sense (detect) weight of laundry using the amplifieddisplacement of the tub.
 2. The washing machine according to claim 1,wherein the amplification unit comprises: a lever configured to berotated about a predetermined shaft in proportion to the displacement ofthe tub to amplify the displacement of the tub; and a fixing memberrotatably coupled to a predetermined region of the lever at one endthereof to form the shaft of the lever.
 3. The washing machine accordingto claim 2, wherein the lever comprises: an input end provided at thetub such that the displacement of the tub is transmitted to the inputend; and an output end provided opposite to the input end to amplify andtransmit the displacement of the tub to the sensor module.
 4. Thewashing machine according to claim 3, wherein the lever is formed suchthat a length from the input end of the lever to the shaft of the leveris shorter than a length from the output end of the lever to the shaftof the lever.
 5. The washing machine according to claim 2, furthercomprising: a damper provide below the tub to dampen vibration, whereinthe damper comprises a cylinder mounted at a bottom of the housing and apiston provided below the tub such that the piston is advanced andretreated in the cylinder.
 6. The washing machine according to claim 5,wherein the piston is coupled to the input end of the lever providedbelow the tub such that the displacement of the tub is transmitted tothe input end of the lever.
 7. The washing machine according to claim 5,wherein the fixing member has the other end fixedly mounted to an outercircumference of the cylinder.
 8. The washing machine according to claim3, wherein the sensor module comprises an optical sensor module mountedat a side of the housing, and the output end of the lever comprises areflection plate corresponding to the optical sensor module.
 9. Thewashing machine according to claim 3, wherein the sensor modulecomprises a capacitance sensor module mounted at a side of the housingand the output end of the lever.
 10. The washing machine according toclaim 9, wherein the capacitance sensor module comprises a firstelectrode plate mounted at the side of the housing and a secondelectrode plate mounted at the output end of the lever such that thesecond electrode plate faces the first electrode plate.
 11. The washingmachine according to claim 10, wherein the capacitance sensor moduleconstitutes an RC circuit and/or an LC circuit using change incapacitance between the first electrode plate and the second electrodeplate.
 12. The washing machine according to claim 3, wherein the sensormodule comprises a resistor sensor module mounted at a side of thehousing and the output end of the lever.
 13. The washing machineaccording to claim 12, wherein the resistor sensor module comprises avariable resistor mounted at the side of the housing and a resistanceadjuster mounted at the output end of the lever such that the resistanceadjuster is connected to the variable resistor to adjust a resistancevalue of the variable resistor.
 14. The washing machine according toclaim 13, wherein the resistor sensor module constitutes an RC circuitor an RR circuit using change in output voltage of the variableresistor.
 15. A washing machine comprising: a housing; a tub provided inthe housing to contain water; a lever having an output end to amplifydisplacement of the tub transmitted to an input end according to inputof laundry into the washing machine; a fixing member coupled to thelever; and a sensor module configured to measure displacement of theoutput end of the lever to sense weight of the laundry.
 16. The washingmachine according to claim 15, wherein the fixing member coupled to apredetermined region of the lever to form a shaft of the lever, whereinthe lever is rotated about the shaft such that the displacement of thetub transmitted to the input end of the lever is amplified at the outputend of the lever.
 17. A laundry amount detection apparatus of a washingmachine, comprising: a sensor module configured to measure descent of atub to sense weight of laundry; a lever configured to be rotated about ashaft to amplify the descent of the tub such that the descent of the tubis sensed by the sensor module; and a fixing member coupled to thelever, wherein, the lever comprises an input end fixedly mounted to thetub such that the descent of the tub is transmitted to the input end andan output end provided opposite to the sensor module.
 18. The laundryamount detection apparatus according to claim 17, wherein the fixingmember rotatably coupled to a predetermined region of the lever at oneend thereof to form the shaft of the lever.
 19. The laundry amountdetection apparatus according to claim 17, wherein the sensor modulecomprises an optical sensor module, and the output end of the levercomprises a reflection plate corresponding to the optical sensor module.20. The laundry amount detection apparatus according to claim 17,wherein the sensor module comprises a capacitance sensor module, and thecapacitance sensor module comprises a first electrode plate having apredetermined size and a second electrode plate mounted at the outputend of the lever such that the second electrode plate corresponds to thefirst electrode plate.
 21. The laundry amount detection apparatusaccording to claim 17, wherein the sensor module comprises a resistorsensor module, and the resistor sensor module comprises a variableresistor and a resistance adjuster mounted at the output end of thelever such that the resistance adjuster is connected to the variableresistor to adjust a resistance value of the variable resistor.